FORTUNE — Adena Friedman is returning to NASDAQ OMX Group Inc. NDAQ , three years after stepping down as chief financial offer to take on the CFO role at private equity firm The Carlyle Group  CG . Her new role will be as president of global corporate, information and tech solutions business. 

While with Carlyle, Friedman was instrumental in the company’s 2012 initial public offering. Not surprisingly, the firm listed on NASDAQ.

This move makes all sorts of sense for Friedman. It basically puts her in the running to eventually run the show at NASDAQ, which probably wasn’t in in the cards at Carlyle (where Glenn Youngkin and new hire Mike Cavanaugh are seen as heirs apparent). Plus, she again gets to run business groups – something she did at Nasdaq before eventually switching to the CFO position.

That said, I was quite surprised to read the announcement. After all, it was just six weeks ago that Carlyle announced a new incentive program for three senior executives – Friedman, Cavanaugh and Youngkin – that was explicitly designed to keep them in the fold. 

“Honestly, money isn’t what drives me to do one job over another,” Friedman explained this morning, during a brief phone call. “I make those decisions based on what will make me really excited about the next 10 years.” 

She adds that the formal job offer came following as NASDAQ board meeting last Wednesday.

I also asked Friedman if she viewed this as a stepping stone to an even high position within NASDAQ, given that Carlyle’s statement about her departure suggested as much (NASDAQ CEO Bob Greifeld’s contract runs through 2017). All she would say about that was: “I’m coming in to be co-president and I must prove myself in that role.”

In related news, Carlyle said that chief accounting officer Curt Buser would serve as interim CFO.

Additional reporting by John Kell.